Parking assist system

ABSTRACT

A parking assist system for a vehicle includes a rearward viewing camera, a display and a controller. When operating in a first mode, the controller generates a first overlay at the displayed images that includes a representation of a target parking position. When the vehicle is in a reverse gear, the controller operates in a second mode and generates second and third overlays at the displayed images. The second overlay includes a representation of a projected rearward path of the vehicle that is based on a current steering angle of the vehicle. When operating in the second mode and after the representation of the target parking position is positioned at a displayed target parking space for the vehicle, the controller determines a target path for the vehicle to guide the driver to the target parking space, with the third overlay including a representation of the determined target path.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/278,110, filed Sep. 28, 2016, now U.S. Pat. No. 9,868,463,which is a continuation of U.S. patent application Ser. No. 14/524,203,filed Oct. 27, 2014, now U.S. Pat. No. 9,457,717, which is acontinuation of U.S. patent application Ser. No. 13/384,672, filed Jan.18, 2012, now U.S. Pat. No. 8,874,317, which is a 371 national phasefiling of PCT Application No. PCT/US2010/043330, filed Jul. 27, 2010,which claims the filing benefit of U.S. provisional application Ser. No.61/228,655, filed Jul. 27, 2009, which are hereby incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

The present invention relates to a parking assist system for use invehicles.

BACKGROUND OF THE INVENTION

Parking assist systems are currently available only on certain luxuryvehicles, and are typically relatively complex systems that are eitherentirely or semi-autonomous, capable of steering and/or driving thevehicle into a parking spot. Such systems typically require significantprocessing power in order to determine a suitable path to follow duringthe parking maneuver. Such systems can be relatively expensive.

It would be advantageous if a parking assist system were available thatrequired relatively less processing power, that was relatively simpler,and was relatively less expensive than some systems of the prior art.

SUMMARY OF THE INVENTION

In a first aspect, the invention is directed to a parking assist systemfor a vehicle, wherein a target parking position overlay is added to arearview scene displayed to the vehicle driver.

In a particular embodiment of the first aspect, the parking assistsystem includes a camera mounted to the vehicle so as to receive arearward scene, a display in the vehicle connected to the camera andconfigured to display an image of the rearward scene, and a controllerconfigured to add an overlay to the image of the rearward scene. Theoverlay includes a representation of a target parking position.

In a second aspect, the invention is directed to a parking assist systemfor a vehicle, that is configured to select a target path for thevehicle driver to follow while parking the vehicle, to inform the driverof the vehicle's projected path based on the vehicle's steering angle,and to inform the driver of whether the projected path matches thetarget path.

In a particular embodiment of the second aspect, the parking assistsystem includes a camera mounted to the vehicle so as to receive arearward scene, a display in the vehicle connected to the camera andconfigured to display an image of the rearward scene, and a controllerconfigured to add an overlay to the image of the rearward scene. Theoverlay includes a representation of a projected path for the vehiclebased on a current vehicle steering angle, and a representation of atarget path for the vehicle.

In a third aspect, the invention is directed to a parking assist systemfor a vehicle, wherein the parking assist system has two modes ofoperation. In a first mode a first overlay is added to a rearview scenedisplayed to the vehicle driver. The first overlay includes arepresentation of a target parking position. In a second mode a secondoverlay is added to the rearview scene displayed to the vehicle driver.The second overlay includes a representation of a projected path for thevehicle based on a current vehicle steering angle, and a representationof a target path segment for the vehicle.

In a particular embodiment of the third aspect, the parking assistsystem includes a camera mounted to the vehicle so as to receive arearward scene, a display in the vehicle connected to the camera andconfigured to display an image of the rearward scene, and a controllerconfigured to operate the parking assist system in two operating modes.In a first operating mode the controller is configured to add a firstoverlay to the image of the rearward scene, wherein the first overlayincludes a representation of a target parking position. In a secondoperating mode the controller is configured to add a second overlay tothe image of the rearward scene, wherein the second overlay includes arepresentation of a projected path for the vehicle based on a currentvehicle steering angle, and a representation of a target path segmentfor the vehicle.

In a fourth aspect, the invention is directed to a parking assist systemfor a vehicle, wherein the parking assist system selects a plurality oftarget path segments for the vehicle to follow to park in a targetparking spot, wherein each target path segment involves the vehiclehaving steering wheels pointed straight or at full lock.

In a particular embodiment of the fourth aspect, the parking assistsystem includes a camera mounted to the vehicle so as to receive arearward scene, a display in the vehicle connected to the camera andconfigured to display an image of the rearward scene, and a controllerconfigured to select a plurality of target path segments for the vehicleto follow to park in a target parking spot. Each target path segmentinvolves the vehicle having the steering wheels pointed straight or atfull lock.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of example only withreference to the attached drawings, in which:

FIG. 1 is a schematic illustration of a parking assist system inaccordance with an embodiment of the present invention;

FIG. 2 is a view of a rearward scene on a display that is part of theparking assist system shown in FIG. 1;

FIG. 3 is a view of a rearward scene on the display shown in FIG. 3,with the parking assist system in a parking spot locator mode;

FIG. 4 is a view of a rearward scene on the display shown in FIG. 3,with the parking assist system in the parking spot locator mode, afterthe vehicle has traveled past a target parking spot;

FIG. 5 is a view of a rearward scene on the display shown in FIG. 3,with the parking assist system in the parking spot locator mode, afterthe vehicle has backed up to a suitable position to park in the targetparking spot;

FIG. 6 is a view of a rearward scene on the display shown in FIG. 3,with the parking assist system in a parking guidance mode, showing thealignment between the projected path of the vehicle with a first targetpath segment for the vehicle;

FIGS. 7a-7d are views of a rearward scene on the display shown in FIG.3, with the parking assist system in the parking guidance mode,illustrating the progression of the vehicle along the first target pathsegment;

FIGS. 8a-8c are views of a rearward scene on the display shown in FIG.3, with the parking assist system in the parking guidance mode, showingthe progression towards alignment between the projected path of thevehicle with a second target path segment for the vehicle;

FIGS. 9a and 9b are views of a rearward scene on the display shown inFIG. 3, with the parking assist system in the parking guidance mode,illustrating the progression of the vehicle along the second target pathsegment;

FIGS. 10a-10d are views of a rearward scene on the display shown in FIG.3, with the parking assist system in the parking guidance mode, showingthe progression towards alignment between the projected path of thevehicle with a third target path segment for the vehicle;

FIG. 11 is a view of a rearward scene on the display shown in FIG. 3,with the parking assist system in the parking guidance mode, showing thevehicle having nearly completed the third target path segment for thevehicle; and

FIG. 12 is a view of a rearward scene on the display shown in FIG. 3,with the parking system in the parking guidance mode, wherein thevehicle is parking in a perpendicular parking spot.

DETAILED DESCRIPTION OF THE INVENTION

Reference is made to FIG. 1, which shows a parking assist system 10 foruse in a vehicle 11, in accordance with an embodiment of the presentinvention. The parking assist system includes a camera 12, a controller14 and a display 16. The camera 12 is positioned on the vehicle 11 forrearward viewing and receives a rearward scene shown at 18. Thecontroller 14 communicates with the camera 12 and sends an image 20 ofthe rearward scene 18 (FIG. 2) to the display 16, which is positioned inthe vehicle cabin. The display 16 is positioned to display the image 20of the rearward scene 18 to the vehicle driver.

When the vehicle driver wants to use the parking assist system 10 (FIG.1), he or she presses a button in the interior of the vehicle 11, whichactivates the parking assist system 10 in a first mode, which is aparking spot locator mode. When in the parking spot locator mode, thecontroller 14 adds an overlay 22 (FIG. 3) to the image 20, which assiststhe driver in finding a suitable parking spot for the vehicle 11 (FIG.1). The overlay 22 (FIG. 3) includes a rectangle 24 which is arepresentation of a target parked position which is offset a selecteddistance behind and a selected distance laterally from the vehicle 11(FIG. 1). The size of the rectangle 24 (FIG. 3) preferably representssubstantially the length and further preferably represents substantiallythe width of the vehicle 11 (FIG. 1).

The overlay 22 (FIG. 3) also includes a line 26 extending along theoutside edge (shown at 28) of the rectangle 24 (i.e., the side edge ofthe rectangle 24 that faces outwardly from the parking spot).

The line 26 extends a selected distance forward of the rectangle 24 anda selected distance rearward of the rectangle 24 and assists the driverof the vehicle 11 in lining up the vehicle 11 to be parallel to theparking lane.

With the overlay 22 shown on the image 20, the driver drives along theroad until he or she finds a potential parking spot, shown at 30 in FIG.4. In the exemplary embodiment shown in the figures, the driver droveforward to find the potential parking spot 30. As shown in FIG. 4, thevehicle 11 has overshot the potential parking spot 30 and so the forwardedge of the rectangle 24 is too far forward, overlapping with thevehicle (shown at 32) that is forward of the potential parking spot 30.Having driven too far forward, the driver may put vehicle 11 (FIG. 1)into reverse gear in order to back up to superimpose the rectangle 24 onthe potential parking spot 30.

When the vehicle is in reverse, a representation 34 of the projectedpath of the vehicle is added to the included in the overlay 22 that isprovided with the image 20 shown on the display 16. The representation34 is based on the steering angle of the vehicle and is updated as thesteering angle changes.

The representation 34 includes several features such as lateral edgelines 36 and distance markers 38. The lateral edge lines 36 correspondto the lateral edges of the vehicle. The distance markers 38 eachcorrespond to a selected distance behind the vehicle, preferably inuniform increments.

As shown in FIG. 5, the vehicle 11 (FIG. 1) has backed up sufficientlyto superimpose the rectangle 24 on the potential parking spot 30. Oncein this position, the driver can see that the vehicle 11 (FIG. 1) hassufficient room to fit in the parking spot 30. It is optionally possiblefor the length of the rectangle 24 to be the length required by thevehicle to fit in the parking spot instead of simply representing thelength of the vehicle 11 (FIG. 1) itself. As will be understood by oneskilled in the art, the length required by the vehicle (FIG. 1) to parkin a spot is some amount longer than the length of the vehicle (FIG. 1)itself.

Once the driver has decided that the parking spot 30 (FIG. 5) issuitable, he or she may press another button on the dashboard toactivate the parking assist system 10 (FIG. 1) in a parking guidancemode, as shown in FIG. 6.

In the parking guidance mode, the parking assist system 10 (FIG. 1)determines a target path for the vehicle 11 to follow in order to parkin the spot delineated by the rectangle 24 (FIG. 6) at the time that theparking guidance mode was initiated.

When in the parking guidance mode, two representations are shown on thedisplay 16. One is the aforementioned representation 34 of the vehicle'sprojected path at the current steering angle. The other is arepresentation shown at 40 a of a segment of the target path to reachthe parking spot delineated by the rectangle 24 (FIG. 5).

Initially, the driver turns the vehicle's steering wheel until theprojected path representation 34 of the vehicle substantially alignswith the target path segment representation 40 a. When they are suitablyaligned, the parking assist system 10 may notify the driver that he/shecan proceed to back the vehicle up along the target path. Alternatively,the alignment of the representations 34 and 40 a visually on the display16 may itself be considered notification to the driver that theprojected path suitably matches the target path.

Referring to FIGS. 7a, 7b, 7c and 7d , as the driver backs the vehicleup progressively along the target path segment, a distal portion 42 ofthe target path representation 40 a change from one color to another,shortening the length of the proximal portion 44 of the representation40 a that remains in the first color. This gives the driver anindication of how much of the target path segment remains to be drivenbefore another phase of the parking maneuver is to be made.

Once the vehicle has driven the entire target path segment, the parkingassist system 10 selects the next segment of the target path for thevehicle to follow, and represents it on the display 16 as therepresentation 40 b shown in FIG. 8a . The second target path segmentrepresentation 40 b guides the driver in the turn-in phase of theparking maneuver. At the point in time shown in FIG. 8a , the vehicle'ssteering wheels are still pointed straight since the first target pathsegment which was just completed was a straight segment. Thus, at thepoint in time shown in FIG. 8a , the driver's projected path representedat 34 is misaligned with the second target path segment represented at40 b.

As the driver turns the steering wheel to align the vehicle's projectedpath with the target path segment, the projected path representation 34becomes progressively aligned with and superimposed with the target pathsegment representation 40 b, as shown in FIG. 8b . After the driverturns the steering wheel sufficiently, the vehicle's projected path isaligned with the vehicle's target path segment, as shown by therepresentations 34 and 40 b in FIG. 8c . The target path segmentillustrated in FIGS. 8a, 8b and 8c may be the path at full wheel lock(i.e., at the maximum steering angle the vehicle is capable of).

FIGS. 9a and 9b show the progress of the vehicle along the second targetpath segment. Once the vehicle has moved along the entire second targetpath segment, the parking assist system 10 selects the next (i.e.,third) target path segment for the vehicle to follow, which isrepresented in FIG. 10a at 40 c. The third target path segment is thetuck-in phase of the parking maneuver and requires that the driver turnthe steering wheel to the opposite limit. FIGS. 10a-10d illustrate thedriver turning the wheel to bring the projected path into alignment withthe third target path segment.

Once the projected path and third target path segment are aligned, thedriver backs the vehicle up along the third target path segment. FIG. 11illustrates the vehicle having completed almost all of the third targetpath segment. After the third target path segment is completed, thedriver has completed the entire parking maneuver. Optionally he/she candrive forward if desired to adjust the spacing between the driver'svehicle and the vehicles in front and behind.

It will be noted that the parking maneuver includes three phases, abackup phase wherein the vehicle is backed up in a straight line (withthe wheels pointing straight), a turn-in phase wherein the vehicle isbacked up at full wheel lock in one direction, and a tuck-in phasewherein the vehicle is backed up at full wheel lock in the otherdirection. Providing target path segments wherein the wheels are pointedstraight or are at full lock simplifies the process of aligning theprojected path with the target path segment, and simplifies keeping thevehicle along the target path segment.

While backing the vehicle up along a target path segment, if the driverfor some reason veers off the target path by more than a selectedamount, the parking assist system 10 notifies the driver, and optionallyaborts the parking maneuver.

Optionally, the parking assist system 10 can permit the driver to selectwhether the parking spot is to the left of the vehicle (as shown in thefigures) or to the right of the vehicle. For a parking spot on the rightof the vehicle, the turn-in and tuck-in phases would be mirror images ofthe turn-in and tuck-in phases illustrated in FIGS. 8a -11.

It will be understood that the three target path segments need not allbe the same length.

It will be noted that the rectangle 24 (FIG. 5) is at a fixed positionbehind and to the side of the vehicle. The target path for the parkingmaneuver is thus the same each time the vehicle is to be parked althoughit may be mirrored in the optional embodiment wherein the parking assistsystem 10 permits selecting a parking spot on the other side (i.e., theright side) of the vehicle. As a result of the consistency in theparking maneuver, the parking maneuver need not be recalculated eachtime the vehicle uses the parking assist system 10. This permits theparking assist system 10 to operate using relatively inexpensive controlhardware and software.

In the above description, the in-cabin display 16 was used as thehuman/machine interface and provided the driver with instructionsvisually/graphically for driving the vehicle into a parking spot. It ispossible to provide instructions to the driver by other means inaddition to or instead of using the in-cabin display 16. For example,the human/machine interface could include a speaker (e.g., from thevehicle's sound system) and could emit audible messages to the drivervia the speaker. Such messages could be instructions in any language,such as English. For example, an instruction could be given audibly toturn the vehicle steering wheel to a selected position (e.g., full lockto the left). It will be noted that such an instruction would in effectinform the driver of the target path for the vehicle. In addition to theaudible messages, or instead of them, a chime or a beep could be emittedat points in the parking process where the driver is supposed to carryout a new maneuver, to let the driver know that he/she is off course, tolet the driver know that he/she is on course (i.e., that the projectedvehicle path matches the target path), or for any other suitablepurpose.

In the above description a method and system were described for parallelparking into a parking spot. It is also possible for an embodiment ofthe invention to be provided for parking into a perpendicular parkingspot 30 (see FIG. 12). A perpendicular parking spot 30 is a parking spotthat is perpendicular to the direction of travel of the vehicle whendriving by. Perpendicular parking spots are typically used in parkinglots for malls, office buildings and the like. In the position shown inFIG. 12, the vehicle has already completed some portion of the parkingprocess and is backing into the parking spot 30.

While the above description constitutes a plurality of embodiments ofthe present invention, it will be appreciated that the present inventionis susceptible to further modification and change without departing fromthe fair meaning of the accompanying claims.

The invention claimed is:
 1. A parking assist system for a vehicle, theparking assist system comprising: a camera mounted to the vehicle so asto have a field of view rearward of the vehicle, wherein the cameracaptures images of a rearward scene rearward of the vehicle; a displayin the vehicle that displays images captured by the camera; acontroller, wherein the controller is activated in a first mode inresponse to actuation of a first user input in the vehicle and isactivated in a second mode in response to actuation of a second userinput in the vehicle; wherein, when operating in the first mode, thecontroller generates a first overlay at the displayed images of therearward scene, and wherein the first overlay includes a representationof a target parking position, and wherein the representation of thetarget parking position is displayed so as to appear offset a selecteddistance behind the vehicle and a selected distance laterally from thevehicle; wherein the representation of the target parking position has alength that represents the length of the vehicle and wherein therepresentation of the target parking position has a width thatrepresents the width of the vehicle; wherein the controller is operablein the first mode while the vehicle is being driven; wherein, whenoperating in the first mode, the vehicle is driven to position therepresentation of the target parking position at a displayed targetparking space for the vehicle; wherein, when the vehicle is in a reversegear, and responsive to actuation of the second user input, thecontroller operates in the second mode, and wherein, when operating inthe second mode, the controller generates a second overlay and a thirdoverlay at the displayed images of the rearward scene; wherein thesecond overlay includes a representation of a projected rearward path ofthe vehicle that is based on a current steering angle of the vehicle;and wherein, when operating in the second mode and after therepresentation of the target parking position is positioned at thedisplayed target parking space for the vehicle, the controllerdetermines a target path for the vehicle to guide the driver to thetarget parking space, and wherein the third overlay includes arepresentation of the determined target path.
 2. The parking assistsystem of claim 1, wherein the representation of the target parkingposition comprises a rectangle.
 3. The parking assist system of claim 2,wherein the first overlay includes a line extending along an outsideedge of the rectangle that extends a selected distance forward andrearward of the rectangle to assist the driver of the vehicle in liningup the vehicle to be parallel to the target parking space.
 4. Theparking assist system of claim 1, wherein the target parking space isparallel to a direction of travel of the vehicle.
 5. The parking assistsystem of claim 1, wherein the target parking space is perpendicular toa direction of travel of the vehicle.
 6. The parking assist system ofclaim 1, wherein the controller informs the driver of the projectedrearward path for the vehicle based on the current steering angle of thevehicle, and informs the driver of whether the projected path matchesthe determined target path.
 7. The parking assist system of claim 6,wherein the controller is operable in the first mode while the vehicleis being driven in a forward direction along the road.
 8. The parkingassist system of claim 6, wherein, when the vehicle is moving along thedetermined target path, the controller adds a representation of theprogress of the vehicle on the determined target path.
 9. The parkingassist system of claim 6, wherein the representation of the projectedrearward path of the vehicle has a width that represents the entirewidth of the vehicle.
 10. The parking assist system of claim 6, whereinthe controller is configured to select a plurality of target pathsegments for the vehicle to follow.
 11. The parking assist system ofclaim 10, wherein the controller informs the driver of the target pathsegments via at least one of the display and a speaker.
 12. The parkingassist system of claim 11, wherein the controller informs the driver ofthe target path segments by instructing the driver to turn the steeringwheel of the vehicle to a selected position.
 13. The parking assistsystem of claim 10, wherein the controller informs the driver of whetheror not the projected rearward path matches the determined target pathvia a speaker.
 14. The parking assist system of claim 10, wherein eachtarget path segment involves the vehicle having steering wheels pointedstraight or at full lock, and wherein the plurality of target pathsegments comprises three target path segments, including a first targetpath segment in which the vehicle is driven straight rearwardly, asecond target path segment in which the vehicle is driven rearwardlywith the steering wheels at full lock in one direction, and a thirdtarget path segment in which the vehicle is driven rearwardly with thesteering wheels at full lock in the opposite direction.
 15. The parkingassist system of claim 14, wherein the length of each target pathsegment remains constant from one parking maneuver to another.
 16. Aparking assist system for a vehicle, the parking assist systemcomprising: a camera mounted to the vehicle so as to have a field ofview rearward of the vehicle, wherein the camera captures images of arearward scene rearward of the vehicle; a display in the vehicle thatdisplays images captured by the camera; a controller, wherein thecontroller is activated in a first mode in response to actuation of afirst user input in the vehicle and is activated in a second mode inresponse to actuation of a second user input in the vehicle; wherein,when operating in the first mode, the controller generates a firstoverlay at the displayed images of the rearward scene, and wherein thefirst overlay includes a representation of a target parking position,and wherein the representation of the target parking position isdisplayed so as to appear offset a selected distance behind the vehicleand a selected distance laterally from the vehicle; wherein therepresentation of the target parking position has a length thatrepresents the length of the vehicle and wherein the representation ofthe target parking position has a width that represents the width of thevehicle; wherein the controller is operable in the first mode while thevehicle is being driven; wherein, when operating in the first mode, thevehicle is driven to position the representation of the target parkingposition at a displayed target parking space for the vehicle; whereinthe first overlay includes a line extending along an outside edge of therepresentation of the target parking position that extends a selecteddistance forward and rearward of the representation of the targetparking position to assist the driver of the vehicle in lining up thevehicle with the target parking space; wherein, when the vehicle is in areverse gear, and responsive to actuation of the second user input, thecontroller operates in the second mode, and wherein, when operating inthe second mode, the controller generates a second overlay and a thirdoverlay at the displayed images of the rearward scene; wherein thesecond overlay includes a representation of a projected rearward path ofthe vehicle that is based on a current steering angle of the vehicle;wherein, when operating in the second mode and after the representationof the target parking position is positioned at the displayed targetparking space for the vehicle, the controller determines a target pathfor the vehicle to guide the driver to the target parking space, andwherein the third overlay includes a representation of the determinedtarget path; and wherein the controller informs the driver of theprojected rearward path for the vehicle based on the current steeringangle of the vehicle, and informs the driver of whether or not theprojected path matches the determined target path.
 17. The parkingassist system of claim 16, wherein the controller is operable in thefirst mode while the vehicle is being driven in a forward directionalong the road.
 18. The parking assist system of claim 16, wherein, whenthe vehicle is moving along the determined target path, the controlleradds a representation of the progress of the vehicle on the determinedtarget path.
 19. A parking assist system for a vehicle, the parkingassist system comprising: a camera mounted to the vehicle so as to havea field of view rearward of the vehicle, wherein the camera capturesimages of a rearward scene rearward of the vehicle; a display in thevehicle that displays images captured by the camera; a controller,wherein the controller is activated in a first mode in response toactuation of a first user input in the vehicle and is activated in asecond mode in response to actuation of a second user input in thevehicle; wherein, when operating in the first mode, the controllergenerates a first overlay at the displayed images of the rearward scene,and wherein the first overlay includes a representation of a targetparking position, and wherein the representation of the target parkingposition is displayed so as to appear offset a selected distance behindthe vehicle and a selected distance laterally from the vehicle; whereinthe representation of the target parking position has a length thatrepresents the length of the vehicle and wherein the representation ofthe target parking position has a width that represents the width of thevehicle; wherein the controller is operable in the first mode while thevehicle is being driven forwardly or rearwardly along a road; wherein,when operating in the first mode, the vehicle is driven to position therepresentation of the target parking position at a displayed targetparking space for the vehicle; wherein, when the vehicle is in a reversegear, and responsive to actuation of the second user input, thecontroller operates in the second mode, and wherein, when operating inthe second mode, the controller generates a second overlay and a thirdoverlay at the displayed images of the rearward scene; wherein thesecond overlay includes a representation of a projected rearward path ofthe vehicle that is based on a current steering angle of the vehicle;wherein, when operating in the second mode and after the representationof the target parking position is positioned at the displayed targetparking space for the vehicle, the controller determines a target pathfor the vehicle to guide the driver to the target parking space, andwherein the third overlay includes a representation of the determinedtarget path; wherein the representation of the determined target pathcomprises a plurality of target path segments for the vehicle to followtoward the target parking space; and wherein, when the vehicle is movingalong the determined target path, the controller adds a representationof the progress of the vehicle on the determined target path.
 20. Theparking assist system of claim 19, wherein the representation of thetarget parking position comprises a rectangle, and wherein the firstoverlay includes a line extending along an outside edge of the rectanglethat extends a selected distance forward and rearward of the rectangleto assist the driver of the vehicle in lining up the vehicle to beparallel to the target parking space.